The analog integrator is a fundamental component in numerous important electronic devices such as analog-to-digital converters (ADCs), control systems, and analog computers. Analog integrators produce output signals that are the time integrals of their input signals. Input signals with high amplitudes may cause conventional analog integrators to produce an output that saturates at the circuit's supply voltage and therefore does not accurately reflect the integral of the input. If not designed properly or carefully, a conventional analog integrator may produce incorrect results given certain input signals because of saturation of its output at the value of its supply voltage. Such saturation could cause errors or inaccuracies.
U.S. Pat. No. 7,555,507 to Bryant et al. (“Bryant”) discloses a technique to prevent the saturation of analog integrator's output. When the output of the analog integrator reaches the threshold voltage, a pre-charged capacitor will be used to reset the output, forcing the output to go to zero. Thus, there would be a sudden discharge for the capacitor of the analog integrator.